This invention pertains to processes for making paddles, and more particularly to efficient processes for making superior quality kayak paddles with composite blades and the kayak paddles made by those processes.
Since the invention of the kayak by the ancient peoples of Alaska and Iceland, there has been a continual effort on the part of kayakers to improve the design and construction of kayak paddles. Efficient paddle design is an optimal balance of minimal weight, maximal strength, optimal stiffness, effective performance in the water, and low cost.
All modern high performance paddles are composite constructions of fiber reinforced resin blades on hollow shafts, also made of fiber reinforced plastic materials. The blade is normally molded in a two-part die machined to the desired blade shape, and the molded blade is then fitted to a purchased paddle shaft. Among the many problems of prior art composite paddles are excessive blade molding time because of the cure time for the resin, and excessive blade weight because of excess resin in the cured blade. The attachment of the blade to the paddle shaft is normally a lengthy, multi-step process fraught with potential for failure.
Accordingly, this invention provides a fast and efficient process for making kayak paddles and a kayak paddle having the desired mechanical properties of strength, light weight, durability and effective propulsion effect.
The invention includes a process for manufacturing paddles, and the paddles made by the process. The process includes making a two-part mold having semi-cylindrical openings for the paddle shaft so that the paddle blade may be molded and co-cured directly on the paddle shaft. The mold surfaces correspond to the ultimate outer mold line of the paddle, and also are designed to express liquid resin from the centerline of the paddle outward toward its edge as the mold closes. The mold closing and heating schedule is designed to partially cure the resin so that it flows outward through the reinforcing fiber at a controlled rate, preventing resin starvation of the fiber reinforcement and ensuring complete expulsion of any bubbles in the reinforcing fiber. The mold is opened and the paddle is removed from the mold. The paddle edge is then trimmed by a high speed CNC router to produce a paddle that conforms exactly to the desired peripheral shape.